Building Information Modeling

In its simplest definition, building information modeling (BIM) is the move from analog to three-dimensional digital design and construction. According to the American Institute of Architects (AIA), Washington, D.C., BIM is a model-based technology that is linked with a database populated with project information. And it is poised to fundamentally change the way projects are designed, managed and built and, moreover, the way project teams communicate with each other.

For years, people designed construction projects in a two-dimensional environment. The advent of computer-aided-design (CAD) technology automated the task of drafting and enabled the designer to build a two-dimensional geometric representation, with lines, arcs symbols, etc., of the project. The concept of layering was eventually introduced to CAD to enable the grouping together of related elements, but more complex information, such as the relationships between those elements, could not be represented. Then, as early as 20 to 30 years ago, three-dimensional project engineering made its way into high-end, proprietary solutions at companies such as Boeing and in the military. Most of those three-dimensional drawings, however, were still geometric descriptions of the environment, without any intelligence associated with them.

“What differentiates BIM from those early 3-D design solutions is its ability to provide object-based, parametric modeling. BIM can take an object and all of the data describing its components and place it in a model that is a virtual, digital description, rather than a simple geometric description of the object,” said Robert Middlebrooks, industry program manager for Autodesk Inc., San Rafael, Calif.

And, according to Ian Howell, CEO and Bob Batcheler, vice president of industry marketing for Newforma Inc., Manchester, N.H., BIM is the latest generation of design systems in which all of the intelligent building objects that combine to make up a building design can coexist in a single “project database” or “virtual building” that captures everything known about the building and provides, in theory, a single, logical, consistent source for all information associated with it.

BIM capabilities

BIM is not just the electronic transfer of paper documents, but, rather, it greatly increases the ability to control and manipulate data and information in an unprecedented way and in an interoperable format, according to “Guidelines for Improving Practice,” Vol. XXXV, No. 2 from Victor O. Schinnerer & Co. Inc., Chevy Chase, Md., an underwriting manager of professional liability and specialty insurance programs.

“When looking at the properties of any object in the BIM model, you can examine all of the details about the object that are embedded into the database,” Middlebrooks said. When the information in the database is changed, the geographical representation of the object simultaneously reflects the object’s new parameters.

Another important capability of BIM is the model’s ability to represent a building in a wide variety of ways. Because the information about the design and all of its components resides in a single digital file, the data can be manipulated to enable the entire project team to analyze early schematic alternatives at the beginning of the project, to analyze predicted energy performance and required electrical loads, and to analyze cost estimates for all of the components and to easily reflect cost changes of design decisions.

“BIM facilitates collaboration in the design and construction of buildings, allowing more stakeholders in the project to have an active role in understanding the building and optimizing the entire design and construction process,” said Forrest Lott, principal of Lott + Barber Architects, Savannah, Ga., and member of the AIA documents committee. In other words, BIM allows the project to be initially built in a virtual world, so the project team members, including the electrical contractor, can better coordinate activities and balance work force requirements. And because the repository of information kept in a BIM model allows various vendors’ products to “talk” to each other, the construction team can analyze the impact an object will have on the entire building.

According to Brad Workman, vice president of global building and plant solutions for Bentley Systems Inc., Exton, Pa., BIM’s greatest benefit is this ability to reduce conflicts.

“BIM allows design issues to be resolved prior to construction, speeds up construction and saves money in the elimination of waste in the construction process,” he said.

BIM in integrated systems

BIM particularly demonstrates its value when designing integrated building systems (IBS) because it allows the designer to virtually analyze all of the integrated building’s components, devices, connections and zones that will be monitored and controlled.

“BIM can build a virtual working model of the entire building’s systems and allow the designer to analyze it for flaws, improvements, efficiency and connectivity,” Middlebrooks said.

Electrical designers, in particular, would find BIM most valuable in its ability to analyze and determine total demand capacity, voltage drops and in performing the calculations necessary to determine the size, scope and shape of the connected, integrated networks. And because IBS are smart systems that are more sustainable and adaptive than traditional building systems, buildings with IBS require analytical programs that enable the electrical contractor to design an intelligent integrated system.

“BIM is an enabling tool that provides intelligent information about a building’s predicted performance and how it and its integrated systems will operate before construction begins,” Workman said.

Even if the electrical contractor isn’t using BIM, but the architect is, the technology can help the contractor find the most efficient runs for large components, such as switchgear, primary conduits and duct work, and to see virtual representations of the spaces available for system integration components. BIM’s inherent collaborative nature enables everyone in the construction chain, from owner, architect, general contractor, electrical contractor and vendors, to have access to the same data in real-time and to analyze construction phasing, cost and constructability, and fabrication issues.

“Because BIM models serve as a repository for all the knowledge gained during design and construction, it works the best when everyone is participating,” Middlebrooks said.

BIM standard development

A charter for a national BIM Standard committee was developed in late 2005 to produce the U.S. National BIM standard.

“Everyone was defining the technology, how it should be used and what it should entail, differently,” said Deke Smith, president of DKS Information Consultants LLC, Herndon, Va., and executive director of the buildingSMART Alliance of the National Institute of Building Sciences, Washington, D.C. The alliance was formed to focus on education and to examine how business processes will need to adapt to take full advantage of these new models as they impact the construction industry. Thirty signatories to the charter, including lawyers, cost engineers, specification writers, engineers, architects and general contractors, began working together to develop a unified description of the holistic BIM approach.

“A key element of the first version of the standard is the industry foundation classes, which describe the objects within the model and provide a standardized requirement for all the information that must be included when describing an object that is entered into the BIM representational model,” Smith said.

The first draft of the standard was released in early 2007 for industry review and comments, many of which came from overseas.

“The National BIM Standard Version 1, Part 1, was released in December 2007, and now that it has been published, Australia and Norway are planning to adopt its core,” Smith said.

Version 1 provides an overview of BIM, its principles, and its methodologies, and discusses the role of interoperability, storing and sharing information, and information assurance. A national standard will ensure that building owners have access to all of the collective information about the mission of the facility and how it was intended to perform, while vendors and project team members are ensured transparent and consistently defined information about the facility to better negotiate contracts and manage projects.

“The next step is, through the standard development consensus process, to examine whether to accept OMNI Class tables in the national BIM Standard for classifying objects,” Smith said.

As efforts grow, involvement from the electrical industry will be critical to ensuring that the standard developed will fulfill the industry’s needs.

Because BIM’s true benefit is to the project owner, the push to adopt the technology across the construction industry will most likely be client-driven. The value, according to Schinnerer, is in the significant building efficiencies and initial costs savings, and extends to the operation and maintenance of the facility. However, for BIM to gain full acceptance, both the construction industry and the law will have to eventually deal with issues, such as the definition of professional services and the design process, the ownership and control of the digital information used in the BIM model, the relationships of the various parties with concurrent design and construction authority, and payment for the creative efforts, control of the information, and assumed or assigned risks.

BREMER, a freelance writer based in Solomons, Md., contributes frequently to ELECTRICAL CONTRACTOR. She can be reached at 410.394.6966 or darbremer@comcast.net.